Towards Sustainable Infrastructure Using Self-healing Ultra-high-performance Concrete (UHPC)—A Review

To achieve net-zero targets in construction, it is essential to utilize low-carbon materials and highly durable systems that minimize lifecycle emissions and depletion of resources. Ultra-high performance concrete (UHPC), developed for achieving the superior strength and durability, offers significant sustainability benefits when enhanced with self-healing capabilities. This review critically examines major self-healing mechanisms in UHPC, including autogenous healing, chemical admixtures, encapsulated healing agents, and microbial calcite precipitation. Each approach is evaluated based on healing kinetics, microstructural improvements, durability enhancement, environmental performance, and overall sustainability contributions. Key factors influencing healing efficacy: crack geometry, healing duration, curing conditions, exposure environment, binder composition, moisture availability, internal curing, and material optimization, are thoroughly discussed. Recent studies demonstrate that self-healing UHPC effectively restores both mechanical and transport properties, achieving crack closure efficiencies exceeding 90% and significantly reducing chloride ion penetration and permeability. These advancements substantially extend infrastructure service life, lower maintenance requirements, and reduce embodied carbon, directly enabling resilient, climate-adapted, low-impact, and sustainable infrastructure solutions aligned with long-term climate goals.